Plasma-Assisted Jet Engine Combustion Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In jet engines, high airflow velocities in combustion chambers hinder combustion efficiency due to unstable lean flames, unburnt fuel, and NOx emissions, which existing technologies struggle to address effectively.
Innovation Solution
A swirler assembly and plasma generator system that ionizes and dissociates air-fuel mixtures within a combustion chamber, using aerodynamic swirl to enhance combustion stability and efficiency by creating a quasi-spatially uniform plasma discharge, thereby reducing unburnt fuel and NOx emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high velocity air enters the combustion chamber, then engine thrust is maintained, but combustion stability deteriorates and flame blow-off occurs
Solution Approach 1:
The plasma generator pre-ionizes and activates the air-fuel mixture before combustion, creating reactive species and reducing ignition delay. This preliminary action prepares the mixture for stable combustion even at high velocities by initiating chemical reactions ahead of time, allowing the flame to establish itself before the high-speed flow can blow it off.
Solution Approach 2:
The plasma generator changes the physical and chemical parameters of the air-fuel mixture by ionizing it and creating active radicals. This parameter change transforms the mixture into a more reactive state that can sustain combustion at higher velocities, effectively decoupling the combustion stability from the air velocity constraint.
2Object-generated harmful factors
If lean air-fuel mixtures are used, then NOx emissions are reduced, but flame stability deteriorates and extinction occurs
Solution Approach 1:
The plasma generator changes the chemical parameters of the lean air-fuel mixture by ionizing it and generating highly reactive radical species. This parameter change compensates for the reduced fuel concentration in lean mixtures, providing sufficient reaction kinetics to maintain flame stability and prevent extinction while preserving the emission benefits of lean combustion.
Solution Approach 2:
The plasma generator replaces the traditional thermal ignition mechanism with a plasma-based initiation mechanism. Instead of relying solely on thermal energy to ignite lean mixtures, the plasma provides direct electronic excitation and radical generation, enabling stable combustion of lean mixtures that would otherwise be too dilute to sustain a flame.
3Productivity
If plasma is used to ionize and dissociate air-fuel mixture, then combustion efficiency is improved, but device complexity increases
Solution Approach 1:
The plasma generator is designed to perform multiple functions simultaneously: ionizing the air-fuel mixture, generating reactive radicals, providing ignition energy, and stabilizing the flame. This multi-functionality consolidates several combustion enhancement mechanisms into a single device, improving combustion efficiency without proportionally increasing system complexity.
Solution Approach 2:
The plasma generator creates a self-sustaining combustion environment by generating the necessary reactive species and ignition energy from the input power. Once initiated, the plasma-assisted combustion process maintains itself through the exothermic reactions, reducing the need for additional control systems or auxiliary components to maintain stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system improves combustion efficiency by stabilizing lean flames, reducing unburnt fuel, and decreasing NOx emissions, leading to fuel savings and enhanced engine performance.
Implementation Method 1
plasma is an electronically excited state of matter in which the electrons from individual atoms are stripped via electrical interactions with the energy source and by collisions with other energized particles
Implementation Method 2
Plasmas are useful at speeding up reactions by transferring the plasma's energy into the vibration translational or rotational energy of reactants
Implementation Method 3
Reactants are reformed by the breaking of bonds and the production of active radicals
Implementation Method 4
The swirler assembly and the at least one plasma generator are arranged such that combustion air enters the swirler assembly inlet, flows through the swirler body, and exits the swirler body through the swirler assembly outlet with aerodynamic swirl
Implementation Method 5
Combustion of the at least partially I/D air-fuel mixture with the combustion air occurs at least partially within the combustion chamber internal volume
Implementation Method 6
Plasmas are useful at speeding up reactions by transferring the plasma's energy into the vibration translational or rotational energy of reactants
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An apparatus for assisting with the combustion of fuel, the apparatus comprising:a fuel nozzle, having a fuel nozzle mixing chamber, a fuel nozzle air inlet, and a fuel nozzle air outlet, the fuel nozzle mixing chamber being in fluid communication with both a fuel nozzle fuel reservoir and the fuel nozzle air inlet, the fuel nozzle air inlet allowing combustion air to flow into the fuel nozzle, wherein fuel from the fuel nozzle fuel reservoir is directed into the fuel nozzle mixing chamber and, inside the fuel nozzle mixing chamber, the fuel combines with air therein to form a fuel-air mixture; at least one plasma generator located at least partially within the fuel nozzle, the plasma generator at least partially ionizing and/or dissociating the mixture to generate at least one of an at least partially ionized air-fuel mixture and an at least partially dissociated air-fuel mixture ("at least partially I/D air-fuel mixture"); a combustion chamber having a combustion chamber inlet in fluid communication with the fuel nozzle air outlet, the combustion chamber having a combustion chamber outlet, the combustion chamber inlet admitting the at least partially l/D air-fuel mixture from the plasma generator into the combustion chamber internal volume; and wherein combustion of the at least partially l/D air-fuel mixture with the combustion air occurs at least partially within the combustion chamber internal volume to responsively produce products, the products exiting the combustion chamber internal volume through the combustion chamber outlet.